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Lubricated Rotary Vane Laboratory Vacuum Systems
button. All vacuum pumps shut down without
a purge cycle, the inlet isolation valves and the
purge valves will close.
NOTE:
If a pump selector switch is in the "AUTO"
position and the pump is NOT running,
placing the selector switch in "PURGE/
OFF" will NOT start the pump or initiate a
15 minute purge cycle.
4B.4.2 Unit and System Shutdown / Alarms
CAUTION
If the panel is energized then dangerous
voltages exist behind the panel door. If
possible, remove power to the panel before
opening. ONLY TRAINED AND QUALIFIED
PERSONS SHOULD OPEN THE ENCLOSURE
DOOR.
Motor Overload
This will shut down the pump in question and
will not re-start the pump until the condition is
corrected and the reset button on the overload
inside the control cabinet is reset. See "Motor
breakers trip constantly" in the Troubleshooting
Section 5.0.
CAUTION - Motor Overload Alarm:
De-energize the faulted vacuum pump and
investigate the reason for fault prior to trying
to restart. Always check motors for shorts -
phase to phase and phase to ground prior
to resetting the overload and starting the
vacuum pump.
High
Discharge
Shutdown
This will shut down the vacuum pump in question
and not restart until the condition is corrected
and the appropriate reset push button is pressed
on the main control panel. Before allowing the
unit to re-start, the condition should be checked
(see "Pump overheats" in the Troubleshooting
4107 9021 88.01
Exhaust
Temperature
Section 5.0). Even after resetting the alarm and
putting the vacuum unit in "AUTO" mode, the
unit may not re-start, depending on system
sequencing and system pressure.
Lag Unit Running Alarm (if enabled)
This alarm will activate if the last available vacuum
pump comes on. In the case of a duplex system,
it will activate when the second pump turns on or
the lag vacuum switch (VS-2) closes. In the case
of a multiplex system, the lag alarm will activate
when the last available unit is required to come
on. For example, in a quadruplex system, if all
four (4) H-P/O-A switches are set to "AUTO", then
the lag alarm will trigger when the fourth unit
comes on. If on the same system, three (3) of the
four (4) H-P/O-A switches are set to "AUTO" and
the other to "PURGE/OFF " or "HAND", then the
lag alarm will activate when the third unit comes
on. To silence the alarm, press the silence push
button. In the event the lag alarm is persistent,
see Troubleshooting section 5.0.
Simplex systems do not have a lag alarm.
4B.5 Vacuum Switch Set Point
Adjustments
The vacuum switch is set at the factory to the
operating point(s) as stated on the wiring diagram
supplied with the unit. It is good practice to cycle
Figure 4B.4 Vacuum Switch
4B-4
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